In order to satisfy the need for people carrying or accommodating objects easily, the prior arts provide a wide variety of bags. According to the differences of usages or of the styles, the wide variety of bags can be roughly classified as a backpack with shoulder straps (such as a school bag or a sports backpack), a handbag with handles (such as a briefcase or a shopping bag), or a clutch bag without shoulder straps or handles (such as a wallet or a purse or a cosmetic bag), etc.
However, for different purposes of use, people always have different types of bags in order to meet the different needs of life and/or work. Correspondingly, the manufacturers designing and manufacturing bags will design and manufacture bags with different usages or structures based on users' different requirements in order to meet their needs.
However, it becomes bothersome to the users to have too many different types of bags instead. For example, if the users need to carry or accommodate different objects, they have to bring and carry a number of different bags, which is relatively inconvenient to use.
Therefore, there is an urgent need to provide a bag that can meet the users' different needs.